Thermal characterization and crystallization kinetics of polyester polyols derived from adipic acid and bio-based succinic acid with 1,4-butanediol and 1,6-hexanediol

Abstract Crystallization kinetics, thermodynamics, and powder XRD measurements were performed on polyester polyols (PESP) made from succinic acid, SA, or adipic acid, AA, with 1,4-butanediol, BDO, or 1,6-hexanediol, HDO, at 2000 Da Mn. The SA BDO PESP exhibited the greatest crystallization supercooling. The Avrami crystallization kinetics n values are 4 or higher, indicative of sporadic nucleation of spherulitic crystals. At similar crystallization t1/2, SA BDO Keq determined from ΔGc is ten times greater and SA HDO is five times greater than AA BDO Keq. AA BDO and AA HDO have equivalent Keq at similar t1/2. Increasing the diol chain length from four carbons to six carbons increases the ΔGc temperature dependence for SA PESP, but has little impact on the ΔGc temperature dependence of AA PESP. Powder XRD shows that these PESPs contain 35%–40% macrocrystals comprised of nanocrystals with average dimensions of 6–10 nm per side.